Permanent magnet proximity switch



y 26, 1964 D. E. REED ETAL 3,134,870

PERMANENT MAGNET PROXIMITY SWITCH Filed June 15, 1962 3 Sheets-Sheet 1INVENTORS DONALD E. REED STANLEY F. REED BYm ATTORNEY y 26, 1964' D. E.REED ETAL 3,134,870

PERMANENT MAGNET PROXIMITY SWITCH Filed June 15, 1962 3 Sheets-Sheet 2INVENTORS DONALD E. REED STANLEY E REED ATTORNEY M y 1964 D. E. REEDETAL 3,134,870

PERMANENT MAGNET PROXIMITY SWITCH Filed June 15, 1962 5 Sheets-Sheet 3INVENTORS DONALD E. REED STANLEY F. REED ATTORNEY United States PatentPERMANENT MAGNET PROXIMITY SWITCH Donald E. Reed, Kensington, Md., andStanley F. Reed,

McLean, Va., assignors to Space Components, Inc.,

Washington, I).C., a corporation of the District of Columbia 7 FiledJune 15, 1962, Ser. No. 202,824 18 Claims. (Cl. 200-87) This inventionrelates to an electromagnetic snap action switch adapted to be actuatedunder the influence of a magnetic field.

According to one embodiment of the invention, an electromagnetic switchis magnetically biased to assume a quiescent or steady state position.Under the influence of an external magnetic field of suificientstrength, the bias is overcome and contacts of the switch assume adifferent configuration. The bias provides stability and the switch thusexhibits special utility in environments subject to vibration.

According to another embodiment of the invention, an electromagneticswitch carries a rotatable actuating magnet whose pole faces spaciallymesh with a plurality of flux buttons on the switch, slight angularmovement of the actuating magnet elfecting actuation of the switch.

According to another embodiment of the invention, an electromagneticswitch carries a sliding magnet whose pole faces spacially mesh with aplurality of flux buttons on the switch, slight movement of the magneteffecting actuation of the switch.

The switch is characterized by the location of all moving elements andall electrical contacts in a completely controlled atmosphere.Typically, this is an inert atmosphere, but may be chosen as a reducingatmosphere. By such a construction, variations in switch operation whichmay be caused by variations in the ambient atmosphere are precluded.

In the drawings:

FIGURE 1 is a perspective view of the magnetic switch of this inventionwith an actuating magnet associated therewith.

FIGURE 2 is a view, partially broken, along line 2--2 of FIG. 1, theswitch being in its quiescent state.

FIGURE 3 is a side elevational view of onecomponent of the switch.

FIGURE 4 is a perspective view of another component of the switch.

FIGURES 5 through 7 are schematic illustrations of the operation of theswitch of FIGURES 1 to 4 inclusive.

FIGURE 8 is a schematic view, similar to FIGURES 5 through 7, showingthe operation of a second embodiment of the invention.

FIGURE 9 is a partially schematic view of a third embodiment of theinvention.

FIGURE 10 is a top plan view of a fourth embodiment of the invention.

FIGURE 11 is an elevational cross-sectional view, partly schematic, ofthe embodiment of FIGURE 10.

FIGURE 12 is a top plan view of a fifth embodiment of the invention.

FIGURE 13 is an elevational cross-sectional view, partly schematic, ofthe embodiment of FIGURE 12.

Referring now to FIGURES 1 and 2 of the drawings, the numeral 10 denotesthe magnetically actuated switch of this invention and includes acircular, fiat cover plate 12 preferably of non-magnetic material suchas nonmagnetic stainless steel. Plate 12 is provided with inserts 14, 16and 18, commonly termed flux buttons, of unmagnetized magnetic materialof low retentivity. These inserts may extend completely through theplate 12, as illustrated, or may be only partially imbedded. The insertsmay be placed in the plate by soldering.

A generally cylindrical shell or wall 20, preferably integral with plate12, terminates in a lower opening. Thus plate 12 and shell 20 define anopen-ended cylindrical member. Preferably, shell 20 is formed of anon-magnetic material. In order to facilitate mounting of the switch theexternal surfaces of shell 20 may be threaded as indicated by thenumeral 22 to facilitate insertion in a suitable mounting element.

The numeral 24 denotes a metallic ring which completely surrounds and ishermetically sealed to the periphery of a glass plate element 26.Numeral 28 denotes a plurality of conductor elements 30, 34 and 38 and atubular vent element 40, all of which pass through 26 in hermeticallysealed relation. Conductors 30, 34 and 38 are adapted to be inserted ina mounting socket and make electrical contact with an external circuitwhich is to be controlled by the switch. Conductors 30 and 34 terminatein flattened portions 35 and 37 respectively to which are aflixedelectrical contact buttons 32 and 36. Conductor 38 extends higher thanconductors 30 and 34 and terminates in a horizontally extending (noteFIGURE 3) pivot element 42.

Referring now to FIGURE 4 of the drawings, the numeral 44 denotes apivotable body element having top faces 46 and 48 inclined to each otherat an angle A (see FIGURE 2). A permanent magnet 50, such as Alnico, isembedded in face 46 with one surface of the magnet preferably in thesame plane as the face 46. Magnet 50 has the polarity indicated althoughit will be understood that it may have the opposite polarity. The otherface 48 of body 44 is provided with a block of magnetic material 52 notpermanently magnetized also having one surface preferably in the sameplane as its face 48.

The numeral 51 denotes a'bushing made of electrically conductingmaterial, for example silver-graphite, extending completely through bodymember 44 and carries a longitudinal bore 53. A pair of copper sheets 54and 56 contact the sides of bushing 51 over a portion of the latterscircumference and extend downwardly side by side. Sheets 54 and 56 carrycontact buttons 58 and 60 adapted to cooperate, respectively, withcontacts 32 and 36 of the base of the switch. Rotary electrical contactis made between pivot 42 and the interior of bushing 51. As shown atFIGURE 3, conductor 38 carries an abutment 39, greatly exaggerated forpurposes of illustration, against which the left end of bushing 51abuts. A washer 41 bears against the right edge of the bushing. Asuitable crimp 43 is made on the end of pivot stud 42 after 44 and 41are placed thereon.

Preferably, the body 44 is formed of an insulating nonmagnetic material,plastic having been found suitable. A plastic marketed under thetradename Dapon is acceptable since it does not give off gases at fairlyhigh temperatures.

In assembly, all of the above described components are cleaned as byultrasonic cleaning with a suitable solvent. Ring 24 is placed in thelower portion of shell 20 and silver solder S is applied and melted byinduction heating. The ring 24, with plate 26 therein, hermeticallyseals the interior of 10, save for the vent tube 40. The switch isplaced in a vacuum oven and baked for four hours at a temperature ofapproximately 400 F. to remove all volatile contaminants. Dry nitrogenis now introduced into vent tube 40 and the interior of the switch isflushed with this nitrogen approximately three or four times. In thelast filling of the interior of the device, a mixture of nitrogen (93percent) and helium (7 percent) is introduced at a positive pressure(10-12 pounds gauge has been found suitable) at room temperature.

The vent tube 40 is now sealed as by crimping or welding and solder maybe added to the crimped portion if desired for more positive sealing.

In practice, 303 Stainless steel has been found suitable as the covermember 12 and shell 20 and silver solder has been found suitable forplacing the flux buttons 14, 16 and 18 in plate 12, hermetically sealingthem therein.

The switch has been found operable at temperatures up to 500 F. and willcarry currents in the order of 15 amperes.

Referring now to FIGURES 5 through 7 of the drawings, the operation ofthe switch will now be given.

FIGURE 5 of the drawings illustrates, wholly schematically, theoperation of the device to yield the quiescent position shown in FIGURE2. The numerals at FIGURE 5 denote their corresponding three-dimensionalcounterparts of FIGURES 1 to 4 inclusive. Flux lines 100 and 102emanating from permanent magnet 56 pass in the conventional direction asillustrated. These lines of flux find an easier path for return throughelement 14 than through flux buttons 16 and 18 since the latter areseparated and are more distant from permanent magnet 50. As well knownto workers in this art, flux lines 100 and 162 tend to diminish inlength and elements 50 and 14 exhibit an attraction for each other. Thisdrawing together compels the body 44 to assume the illustrated positionin FIGURE 2.

FIGURES 6 and 7 illustrate the operation of the magnetic switch of thisinvention under the influence of an external magnetic field such assupplied by magnet M of FIGURE 1.

Referring now to FIGURE 6, it will be assumed that an external actuatingmagnetic field has the indicated polarity, the dotted lines indicatingthat the illustrated N and S poles are from the same magnet. The fluxlines emanating from the left portion of the external north pole divide,part going through the flux button 14 and part going through the magnet50 in the indicated direction to the left portion of the external southpole. The flux lines emanating from the right portion of the externalnorth pole pass first through flux button 18 thence through element 52and thence through flux button 16 to the right portion of the externalsouth pole to thus complete the magnetic circuit. Because nearly all ofthe magnetic fiux lines from the right portion of the external magneticfield pass through element 52 while only a portion of the flux linesfrom the left portion of the external magnetic field pass through magnet50 (the remainder of the flux lines from the left portion of theexternal magnetic field passing along the length of flux button 14)there will be a greater upward force acting on element 52 than onpermanent magnet 50, if the strength of the external actuating field issufiicient to overcome the biasing action described with reference toFIGURE 5, and thus the body 44 will assume a position opposite to thatillustrated in FIGURE 2 and contact 60 will now abut contact 36 thusforming a new electrical path through the switch.

Reference now to FIGURE 7 of the drawings illustrates that the positionof the switch is changed from its quiescent or steady state positioneven though the polarity of the external magnetic field may be oppositeto that illustrated in FIGURE 6. Nearly all of the magnetic lines offorce emanating from the right portion of the external north pole passthrough flux button 16, element 52, flux button 18 and thence return tothe right portion of the external south pole. Nearly all of the fiuxlines from the left portion of the external north pole pass through fluxbutton 14 and thence to the left portion of the external south pole. Fewor none pass through permanent magnet 50 in the indicated direction,since it is both more remote than flux button 14 and the fiux lines arein opposition to the field of permanent magnet 50, as illustrated by theshortest curved lines. The upward force on element 52 will be greaterthan the upward force on element 50 because there are more flux linesthreading through 16 and 18 and 52 than through 14 and 4 50 and theswitch will assume a position opposite to that illustrated in FIGURE 2and a new electrical path will be established in the switch.

It will be observed that the presence of the elongated flux button 14also serves to protect the magnet 50 lying directly beneath. As apparentfrom the above discussion, no matter what the direction of lines of fluxfrom the external actuating field, a portion of these flux lines alwayspasses through flux button 14 thereby serving to weaken the effect orinfluence of these lines upon permanent magnet 50. Thus, referring toFIGURE 7, in a case wherein the external field acts in a directioncounter to the field of permanent magnet 5-0, the presence of the fluxbutton 14 serves to divert or divide the external flux lines thusweakening their effect upon magnet 50 and preventing it from becomingdemagnetized.

In the description of FIGURES 6 and 7, it has been assumed that theexternal actuating field has been of a width to span the entire fluxbutton array. Thus, in FIGURE 6, the north pole of the externalactuating magnet has been assumed to be wide enough to span the distancefrom fiux button 18 to flux button 14, similarly, its south pole hasbeen assumed to be wide enough to span the distance between flux button16 and flux button 14. In the preferred manner of operation, it is notnecessary that the external actuating field emanate from such wide polefaces. Thus, referring to FIGURE 1 of the drawings, the external magnetM may lie directly over flux buttons 16 and 18 and not extend over fiuxbutton 14. It will be clear, from the previous discussion, that if anarrower actuating field is employed acting directly above flux buttons16 and 18 of FIGURES 6 and 7, the switch will be actuated away from thebias position whether it has the polarity indicated at FIGURE 6 or thepolarity indicated at FIGURE 7 if the actuating field is strong enough.

FIGURE 8 of the drawings illustrates a second embodiment of theinvention, similar in all structural respects to the first embodimentsave for the presence of two flux buttons and 141 in lieu of the singleflux button 14. Flux buttons 140 and 141 occupy the same positions asfiux button 14 with respect to magnet 50 and plate 12. In thisembodiment of the invention, the magnetic saturation of element 52 ischosen to be greater than that of permanent magnet 50. More flux linesfrom a sufficiently strong external actuating field will thence threadthrough element 52 than through magnet 56 regardless of the polarity,i.e., that of FIGURE 6 or that of FIGURE 7, of the external actuatingfield. Hence the quiescent biasing force, that due to the attractionbetween magnet 50 and flux buttons 140 and 141, will be overcome and theswitch actuated under the influence of the external actuating field nomatter what its orientation if the strength of the external field isgreat enough.

FIGURE 9 of the drawings illustrates a third embodiment of theinvention. Referring now to FIGURE 9, the numeral 440 denotes a bodyelement similar in configuration to element 44 of the first embodiment.In lieu of a single permanent magnet 50 and an unmagnetized magneticelement 52, two permanent magnets 590 and 501 are illustrated asoccupying the same positions as ele ments 50 and 52 respectively (noteFIGURE 4). Flux buttons 160, 161, and 181, occupy positions homologousto those indicated at FIGURE 8 of the drawings, the fluxbuttons beingpositioned in the cover plate 12, the latter being omitted from thedrawing for purposes of clarity. The numerals 200, 202, 204 and 206denote pole faces of annular permanent magnet 268 having the indicatedpolarities. The dashed line representations of pole faces 200, 202, 204and 206 show their positions relative to the other elements whenpermanent magnet 208 is in its operative position, i.e., its upperportion tilted toward the viewer so that its pole faces lie in a planeparallel to and slightly above the plane of the flux buttons. The polefaces are integral with the annular magnet 208 and extend downwardlytherefrom as illustrated.

In order to actuate the magnetic switch of this embodiment, the magnet208 (when in its operative position) is rotated counter clockwise. Thepole faces will then occupy positions superposed with respect to theflux buttons. Thus, face 202 moves towards button 161, face 200 movestowards button 160, face 206 moves towards button 180 and face 204 movestowards button 181. The flux lines emanating from face 206 pass throughbutton 180 and then to the south pole of magnet 501, thence to the northpole ofv magnet 501, up through button 160 and enter magnet 208 throughface 200. Magnet 501 thus moves towards buttons 160 and 180 while theflux from faces 2G2 and 204 causes magnet 500 to move away from buttons161 and 181. The upper portion of body 440 thus rotates in the directionof arrow A. In order to reverse the rotation of body 440, magnet 208 isrotated clockwise.

Upon return of annular magnet 208 to the illustrated central position(faces 206, 200, 202, 204 not lying over but spaced between buttons 161,181, 180, 166)), the body 440 remains in the last position assumed, dueto the greater flux passing from magnet 500 (or 501) through theassociated nearby flux buttons, as compared to flux from magnet 501 (or500) through the slightly more distant flux buttons.

Hence body 440 can assume either of two quiescent positions, theposition assumed being dependent on the previous rotation of magnet 208.I

If desired, less than all of the pole faces 209-206 may be employed,although the operation is then somewhat less reliable.

The radius of the concave pole faces identified as 210 very closelyapproximates the radius of the flux buttons and hence only slightangular movement of magnet 203 is required to actuate the switch.Actuating magnet 298 may be mounted directly on the switch or it may becoupled to a shaft or other rotatable member fixedly positioned relativeto the switch.

Referring now to FIGURES l0 and 11 of the drawings, still anotherembodiment of the invention is illustrated which employs a translatingor sliding actuating magnet 227 in lieu of the rotary magnet 20% in theembodiment of FIGURE 9. Permanent magnet 227 has six pole faces 221,222, 223, 224, 225 and 226 with polarities N, S, N, S, N and S, asindicated at FIGURE 10. When the actuating magnet is moved to the right,direc tion B, pole face 221 moves closer to flux button 161, pole face222 moves closer to flux button 160, pole face 224 moves closer to fluxbutton 181 and pole face 225 moves closer to flux button 180. It will beunderstood that the flux buttons shown are mounted in plate 12, in thesame manner as in the embodiment of FIGURE 9. With movement of actuatingmagnet 227 to the right, north pole face 221 moves towards flux button161 so that the flux emanating from pole face 221 passes through thisflux button and repels the north pole N of magnet 500 situated inrotatable member 440. Similarly, south pole face 224 moves towards fluxbutton 181 and here also repulsion exists, now with the south pole S ofmagnet 500. Hence magnet 500 is repelled from flux buttons 161 and 181.South pole face 222 moves towards flux button 160 and the north pole Nof permanent magnet 501 and. attraction exists. Similarly, north poleface 225 moves towards 180 and the south pole S of permanent magnet 501is attracted. This results in upward movement of magnet 501 towards fluxbuttons 160 and 180. Thus rotation of the body 440, indicated by A ofFIG- URE 11, occurs and the switch is actuated to a new position.

From the above described sequence, it is believed obvious that rotationin a direction opposite to A of FIG- URE 11 will occur when actuatingmagnet 227 is moved to the left, direction C.

With actuating magnet 227 in a central position, i.e.,

the position indicated at FIGURE 10, the body 440 will remain in itslast assumed position. The edges of the pole faces are so contoured asto closely complement the periphery of flux buttons 160, 161, 180 and181, as in the embodiment of FIGURE 9, so that only slight translatingmotion in either direction is required to effect the switch actuation.

From a consideration of this embodiment of the invention, it will beappreciated that if magnet 227 is rotated such that flux button 180 liesbetween pole faces 224 and 225 and flux button 181 lies between polefaces 221 and 222, etc., the actuation of body 440 is caused by motionof magnet 227 in the direction at right angles to the indicateddirections B and C.

Referring now to FIGURES l2 and 13 of the drawings, still anotherembodiment of the invention is illustrated which employs anothermodification of a translating actuating magnet. Except for the reversalof the polarity of magnet 561 from the polarity shown in FIGURE 9, thisembodiment is similar to the embodiments of FIGURES 9 and 10 save forthe specific configuration of the actuating magnet. The numeral 337denotes an actuating magnet adapted to travel along a path substantiallyparallel to the plane of flux buttons 160, 161, 180 and 181 placed inthe plate 12 (not illustrated). Magnet 337 is provided with three ridgeportions extending completely thereacross, the lower faces of whichdefine magnetic pole faces 329, 331 and 333 having the indicatedpolarities. Preferably, in order to effect switch actuation upon onlyslight movement of the actuator, the ridges include curved sidescomplementary to the flux buttons, one side of which is indicated by thenumeral 335 in FIGURE 12. The poles of the permanent magnets which liein body 440, and which are situated below the flux buttons, havepolarities as in dicated at FIGURE 12 by N and S.

Referring now to FIGURE 12, upward motion shown byarrow A of actuator337 causes pole face 333 to move closer to flux buttons 18%) and 181,similarly, pole face 331 moves closer to fiux buttons and 161.Considering now the left portion of FIGURE 12, it will be seen thatupward motion results in an attraction of magnet 500 carried byrotatable body 440 while magnet 501 also carried by rotatable body 440,will be repelled. Thus the switch will be actuated. It is believedapparent that downward motion shown by arrow B will result in rotationof body 440 in a counter direction. The body 44.0 will remain in itslast assumed position whenever actuating magnet 337 assumes a centralposition.

' We claim:

1. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell,said cover plate of non-magnetic material and having three aperturestherein, one of said three apertures being' substantially larger thanthe other two of said three apertures, said apertures being arranged toform a generally quadrangular configuration, and an insert of magneticmaterial sealed within each of said three apertures; an armaturerotatably mounted within and supported by said shell, said armaturecomprising a body element of non-magnetic material, an elongatedpermanent magnet, a block of unmagnetized magnetic material, and aswitch arm carrying a pair of electrical contacts mounted on said bodyelement; two electrical contacts mounted within and supported by saidshell; and said armature so correlated to said cover plate that thelarger one of said three inserts is positioned over said permanentmagnet and said other two of said inserts are each positioned over saidblock of magnetic material, whereby the application of an orientedmagnetic field of a predetermined strength across said cover plate willactuate said switch and cause one of said pair of electrical contacts onsaid switch arm to engage one of said two electrical contacts supportedby said shell.

2. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate 7 integral with saidshell, said cover plate of non-magnetic material and having threeapertures therein, and an insert of magnetic material sealed within eachof said three apertures; an armature rotatably mounted within saidshell, said armature comprising a body element, a permanent magnet, ablock of magnetic material, and an electrical contact mounted on saidbody element; an electrical contact mounted within said shell; and saidarmature so correlated to said cover plate that one of said threeinserts is positioned over said permanent magnet and two of said insertsare positioned over said block of magnetic material, whereby theapplication of an oriented magnetic field of a predetermined strengthacross said cover plate will actuate said switch and cause saidelectrical contact on said body element to engage said electricalcontact mounted within said shell.

3. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell,said cover plate of non-magnetic material and having three aperturestherein, one of said three apertures being substantially elongated andlarger than the other two of said three apertures, said apertures beingarranged to form a generally quadrangular configuration, with theelongated apertures along one side thereof, and an insert of magneticmaterial sealed Within each of said three apertures; an armaturerotatably mounted within and supported by said shell, said armaturecomprising a body element of non-magnetic insulating material, anelongated permanent magnet, an elongated block of unmagnetized magneticmaterial, said magnet and said block being aligned, and a switch armcarrying a pair of electrical contacts mounted on said body element; twoelectrical contacts mounted within and supported by said shell; and saidarmature so correlated to said cover plate that the largerone of saidthree inserts is aligned with and positioned over said permanent magnetand said other two of said inserts are aligned with and positioned oversaid block of magnetic material, whereby the application of an orientedmagnetic field of a predetermined strength across said cover plate willactuate said switch and cause one of said pair of electrical contacts onsaid switch arm to engage one of said two electrical contacts supportedby said shell.

4. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell,said cover plate of non-magnetic material and having four aperturestherein, said four apertures being arranged to form a generallyquadrangular configuration, and an insert of magnetic material sealedwithin each of said four apertures; an armature rotatably mounted withinand supported by said shell, said armature comprising a body element ofnon-magnetic material, an elongated permanent magnet, a block ofunmagnetized magnetic material having a magnetic saturation greater thanthat of said permanent magnet, and a switch arm carrying a pair ofelectrical contacts mounted on said body element; two electricalcontacts mounted within and supported by said shell; and said armatureso correlated to said cover plate that two of said four inserts arepositioned over said permanent magnet and two of said four inserts arepositioned over said block of magnetic material, whereby the applicationof an oriented magnetic field of a predetermined strength across saidcover plate .will actuate said switch and cause one of said pair ofelectrical contacts on said switch arm to engage one of said twoelectrical contacts supported by said shell.

5. In an electrical switch operable by a magnetic actuator, thecombinationcomprising: a shell; a cover plate integral with said shell,said cover plate of non-magnetic material and having four aperturestherein, and an insert of magnetic material sealed within each of saidfour apertures; an armature rotatably mounted within said shell, saidarmature comprising a body element, a permanent magnet, a block ofmagnetic material having a magnetic saturation greater than that of saidpermanent magnet,

and an electrical contact mounted on said body element; an electricalcontact mounted within said shell; and said armature so correlated tosaid cover plate that two of said four inserts are positioned over saidpermanent magnet and two of said four inserts are positioned over saidblock of magnetic material, whereby the application of an orientedmagnetic field of a predetermined strength across said cover plate willactuate said switch and cause said electrical contact on said bodyelement to engage said electrical contact mounted within said shell.

6. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell,said cover plate of non-magnetic material and having four aperturestherein, said four apertures being arranged to form a generallyquadrangular configuration, and an insert of magnetic material sealedwithin each of said four apertures; an armature rotatably mounted Withinand supported by said shell, said armature comprising a body element ofnon-magnetic insulating material, an elongated permanent magnet, anelongated block of unmagnetized magnetic material having a magneticsaturation greater than that of said permanent magnet, said magnet andsaid block being aligned, and a switch arm carrying a pair of electricalcontacts mounted on said body element; two electrical contacts mountedWithin and supported by said shell; and said armature so correlated tosaid cover plate that two of said four inserts are aligned with andpositioned over said permanent magnet and two of said four inserts arealigned with and positioned over said block of magnetic material,whereby the application of an oriented magnetic field of a predeterminedstrength across said cover plate will actuate said switch and cause oneof said pair of electrical contacts on said switch arm to engage one ofsaid two electrical contacts supported by said shell.

7. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell,said cover plate of non-magnetic material and having four aperturestherein, said four apertures being arranged to form a generallyquadrangular configuration, and an insert of magnetic material sealedwithin each of said four apertures; an armature rotatably mounted withinand supported by said shell, said armature comprising a body element ofnon-magnetic material, a pair of elongated permanent magnets and aswitch arm carrying a pair of electrical contacts mounted on said bodyelement; two electrical contacts mounted within and supported by saidshell; and said armature so correlated to said cover plate that two ofsaid four inserts are positioned over one of said pair of permanentmagnets and the other two of said four inserts are positioned over theother of said pair of permanent magnets, whereby the application of anoriented magnetic field of a predetermined strength across said coverplate will actuate said switch and cause one of said pair of electricalcontacts on said switch arm to engage one of said two electricalcontacts supported by said shell.

8. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell,said cover plate of non-magnetic material and having four aperturestherein, and an insert of magnetic material sealed within each of saidfour apertures; an armature rotatably mounted within said shell, saidarmature comprising a body element, a pair of permanent magnets and anelectrical contact mounted on said body element; an electrical contactmounted within said shell; and said armature so correlated to said coverplate that two of said four inserts are positioned over one of said pairof permanent magnets and the other two of said four inserts arepositioned over the other of said pair of permanent magnets, whereby theapplication of an oriented magnetic field of a predetermined strengthacross said cover plate will actuate said switch and cause saidelectrical contact on said body element to engage said electricalcontact mounted within said shell. 7

9. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell,said cover plate of non-magnetic material and having four aperturestherein, and an insert ofnmagnetic material sealed within each of saidfour apertures; an armature rotatably mounted within said shell, saidarmature comprising a body element, a pair of permanent magnets and anelectrical contact mounted on said body element; an electrical contactmounted within ,saidshell; said armature so correlated to said coverplatethat two of said four'inserts are positioned over one of saidpairofpermanent magnets and the othertwo of said "four inserts arepositioned over the other of said pair of permanent magnets; and amagnetic actuator operatively associated with said'cover plate and saidarmature, said'actuator comp-rising an annular magnet having four polefaces depending therefrom, said pole faces spaced in a manner so thatthey may either be spatially positioned between said four inserts orsuperposed thereover, and so polarized that adjacent pole faces are ofpposite polarity, whereby the rotation of said actuator with respect tosaid cover plate will actuate said switch and cause-said electricalcontact on said body element to engage said electrical contact mountedwithin said shell. 10. ,In an electrical switch operable by a magneticactuator, the combination comprising: a shell; a cover plate integralwith'said shell, said cover plate of nonmagnetic material and havingfour apertures therein, said four apertures beingv arranged to form agenerally quadrangular configuration, and an insert of magnetic materialsealed within each, of said four apertures; an armature rotatablymounted Within and supported by said shell, ,said armature comprising abody element of non-magnetic material, a pair of elongated permanentmagnets and a switch arm carrying a pair of electrical contacts mount-;ed on said body element; two electrical contacts mounted within andsupported by said'shell; said armature so correlated to said cover platethat two of said four inserts are positioned over one of said pair ofpermanent magnets and the other two of said four inserts are positionedover the other of saidpair of permanent magnets; and a magnetic actuatoroperatively associated with said cover plate and said armature, saidactuator comprising an annular magnet having four pole faces dependingtherefrom, said pole faces spacedin a manner so that they may :either bespatially positioned between saidfour inserts or superposed thereover,so polarized that adjacent pole faces are of opposite polarity and soconfigured that the edge surfaces-thereof closely conform to theconfiguration of the inserts adjacent thereto, whereby the rotation ofsaid actuator with respect to said cover plate will actuate said switchand cause one of said pair of electrical contacts on said switch arm toengage one of said pair :of electrical contacts mounted within saidshell.

1 1. In an electrical switch operable by a magnetic actuator, thecombinationcomprising: a shell; a cover plate integral with said shell,said cover plate of nonmagnetic material and having four aperturestherein, and an insert of magnetic material sealed within each of saidfour apertures; an armature rotatably mounted within said shell, saidarmature comprising a body element, a pair of permanent magnets and anelectrical contact mounted onsaid body element; an electrical contactmounted within said shell; said armatureso correlated to said coverplate that two of said four inserts are positioned over one of said pairof permanent magnets and the other two of said 'four'inserts arepositioned over the other of said pair of permanent magnets; and amagnetic actuator operatively associated with said cover plateand saidarmature, said actuator comprising a generally rectangular magnet'havingsiX1pole faces depending therefrom, said pole faces spaced in twoparallel lines of three each so that said pole faces may either bespatially positioned to surround said four inserts or four of said siXpole faces be super- ,posed thereover, and so polarized that adjacentpole faces are of opposite polarity, whereby the translation of saidactuator with respect to said cover plate will actuate said switch andcause said electrical contact on said body element to engage saidelectrical contact mounted within said shell.

12. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell,said cover plate of nonmagnetic material and having four aperturestherein, said four apertures being arranged to form a generallyquadrangular configuration, and an insert of magnetic material sealedwithin each of said four apertures; an armature rotatably mounted withinand supported by said shell, said armature comprising a body element ofnon-magnetic material, a pair of elongated permanent magnets and aswitch arm carrying a pair of electrical contacts mounted on said'bodyelement; two electrical contacts mounted within and supported by saidshell; said armature so correlated to said cover plate that two of saidfour inserts are positioned over one of said pair ofvpermanent magnetsand the other two of said four inserts are positioned over the other ofsaid pair of permanent magnets; and a magnetic actuator operativelyassociated with said cover plate and said armature, said actuatorcomprising a generally rectangular magnet having six pole facesdepending therefrom, said pole faces spaced in two parallel lines ofthree each so that said pole faces may either be spatially positioned tosurround said four inserts or four of said six pole faces be superposedthereover, so polarized that adjacent pole faces are of oppositepolarity and so configured that the edge surfaces thereof closelyconform to the configuration of the inserts adjacent thereto, wherebythe translation of said actuator with respect to said cover plate willactuate said switch and cause one of said pair of electrical contacts onsaid switch .arm to engage one of said pair of electrical contactsmounted within said shell.

13. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell,said cover plate of non-magnetic material and having four aperturestherein, and an insert of magnetic material sealed within each of saidfour apertures; an armature rotatably mounted within said shell, saidarmature comprising a body element, a pair of permanent magnets and anelectrical contact mounted on said body element; an electrical contactmounted within said shell; said armature so correlated to said coverplate that two of said four inserts are positioned over one of said pairof permanent magnets and the other two of said four inserts arepositioned over the other of said pair of permanent magnets; and amagnetic actuator opera- .tively associated with said cover plate andsaid armature,

said actuator comprising a generally rectangular magnet having threegenerally rectangular pole faces depending therefrom, said pole facesspaced so that said pole faces may either be spatially positioned tosurround said four inserts or two of said three pole faces be superposedthereover, and so polarized that adjacent pole faces are of oppositepolarity, whereby the translation of said actuator with respect to saidcover plate will actuate said switch and cause said electrical contacton said body element to engage said electrical contact mounted Withinsaid shell.

14. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell,said cover plate of non-magnetic material and having four aperturestherein, said four apertures being arranged to form a generallyquadrangular configuration, and an insert of magnetic material sealedwithin each of said four apertures; an armature rotatably mounted withinand supported by said shell, said armature comprising a body element ofnon-magnetic material, a pair of elongated permanent magnets and aswitch arm carrying a pair of electrical contacts mounted on said bodyelement; two electrical contacts mounted within and supported by saidshell; said armature so correlated to said cover plate that two of saidfour inserts are positioned over one of said pair of permanent magnetsand the other two of said four inserts are positioned over the other ofsaid pair of permanent magnets; and a magnetic actuator operativelyassociated with said cover plate and said armature, said actuatorcomprising a generally rectangular magnet having three generallyrectangular pole faces depending therefrom, said pole faces spaced sothat said pole faces may either be spatially positioned to surround saidfour inserts or two of said three pole faces be superposed thereover, sopolarized that adjacent pole faces are of opposite polarity and soconfigured that the edge surfaces thereof closely conform to theconfiguration of the inserts adjacent thereto, whereby the translationof said actuator with respect to said cover plate will actuate saidswitch and cause one of said pair of electrical contacts on said switcharm to engage one of said pair of electrical contacts mounted withinsaid shell.

15. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell,said cover plate of non-magnetic material and having four aperturestherein, and an insert of magnetic material sealed within each of saidfour apertures, an armature rotatably mounted within said shell, saidarmature comprising a body element, a pair of substantially elongatedpermanent magnets and an electrical contact mounted on said bodyelement, each of said pair of magnets having two ends with a north poleat one end and a south pole at the other end, said magnets aligned inparallel relation with the south pole of one magnet positioned adjacentthe south pole of the other magnet, the poles thereof forming agenerally rectangular configuration; an electrical contact mountedwithin said shell; said armature so correlated to said cover plate thattwo of said four inserts are positioned over one of said pair ofpermanent magnets and the other two of said four inserts are positionedover the other of said pair of permanent magnets; and a magneticactuator operatively associated with said cover plate and said armature,said actuator comprising a generally rectangular magnet having six polefaces depending therefrom; said pole faces spaced in two parallel linesof three each so that said pole faces may either be spatially positionedto surround said four inserts or four of said six pole faces besuperposed thereover, and so polarized that adjacent pole faces are ofopposite polarity, whereby the translation of said actuator with respectto said cover plate Will actuate said switch and cause said electricalcontact on said body element to engage said electrical contact mountedwithin said shell.

16. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell,said cover plate of nonmagnetic material and having four aperturestherein, said four apertures being arranged to form a generallyquadrangular configuration, and an insert of magnetic material sealedwithin each of said four apertures, an armature rotatably mounted withinand supported by said shell, said armature comprising a body element ofnonmagnetic material, a pair of substantially elongated permanentmagnets and a switch arm carrying a pair of electrical contacts mountedon said body element, each of said pair of magnets having two ends witha north pole at one end and a south pole at the other end, said magnetsaligned in parallel relation with the south pole of one magnetpositioned adjacent the south pole of the other magnet, the polesthereof forming a gencrally quadrangular configuration; two electricalcontacts mounted within and supported by said shell; said armature socorrelated to said cover plate that two of :said four inserts arepositioned over the ends of one of said pair of permanent magnets andthe other two of :said four inserts are positioned over the ends of theother of said pair of permanent magnets; and a magnetic actuatoroperatively associated with said cover plate and said armature, saidactuator comprising a rectangular magnet having six pole faces dependingtherefrom, said pole faces spaced in two parallel lines of three each sothat said pole faces may either be spatially positioned to surround saidfour inserts or four of said six pole faces be superposed thereover, sopolarized that adjacent pole faces are of opposite polarity and soconfigured that the edge surfaces thereof closely conform to theconfiguration of the inserts adjacent thereto, whereby the translationof said actuator with respect to said cover plate will actuate saidswitch and cause one of said pair of electrical contacts on said switcharm to engage one of said pair of electrical contacts mounted withinsaid shell.

17. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell,said cover plate of nonmagnetic material and having four aperturestherein, said four apertures being arranged to form a generallyquadrangular configuration, and an insert of magnetic material sealedwithin each of said four apertures; an

armature rotatably mounted within and supported by said shell, saidarmature comprising a body element of non-magnetic material, a pair ofsubstantially elongated permanent magnets and a switch arm carrying apair of electrical contacts mounted on said'body element, each of saidpair of magnets having two ends with a north pole at one end and a southpole at the other end, said magnets aligned in parallel relation withthe south pole of one magnet positioned adjacent the north pole of theother magnet, the poles thereof forming a generally rectangularconfiguration; two electrical contacts mounted within and supported bysaid shell; said armature so correlated to said cover plate that two ofsaid four inserts are positioned over the ends of one of said pair ofpermanent magnets and the other two of said four inserts are positionedover the ends of the other of said pair of permanent magnets; and amagnetic actuator operatively associated with said cover plate and saidarmature, said actuator comprising a generally rectangular magnet havingthree generally rectangular pole faces depending therefrom, said polefaces spaced so that said pole faces may either be spatially positionedto enclose said four inserts or two of said three pole faces besuperposed thereover, so polarized that adjacent pole faces are ofopposite polarity and so configured that the edge surfaces thereofclosely conform to the configuration of the inserts adjacent thereto,whereby the translation of said actuator with respect to said coverplate will actuate said switch and cause one of said pair of electricalcontacts on said switch arm to engage one of said pair of electricalcontacts mounted within said shell.

18. In an electrical switch operable by a magnetic actuator, thecombination comprising: a shell; a cover plate integral with said shell;said cover plate of nonmagnetic material and having four aperturestherein, and an insert of magnetic material sealed within each of saidfour apertures; an armature rotatably mounted within said shell, saidarmature comprising a body element, a pair of substantially elongatedpermanent magnets and an electrical contact mounted on said bodyelement, each of said pair of magnets having two ends with a north poleat one end and a south pole at the other end, said magnets aligned inparallel relation with the south pole of one magnet positioned adajcentthe north pole of the other magnet, the poles thereof forming agenerally rectangular configuration; an electrical contact mountedwithin said shell; said armature so correlated to said cover plate thattwo of said four inserts are positioned over the ends of one of saidpair of permanent magnets and the other two of said four inserts arepositioned over the ends of the other of said pair of permanent magnets;and a magnetic actuator operatively associated with said cover plate andsaid armature, said actuator comprising generally rectangular magnethaving three generally rectangular pole faces depending therefrom, saidpole faces spaced so that said pole faces may either be spatiallypositioned to enclose said four inserts or two of said three pole facesbe superposed thereover, and so polarized that adjacent pole faces areof opposite polarity, whereby the translation of said actuator withrespect to said cover plate will actuate said switch and cause saidelectrical contact on said body element to engage said electricalcontact mounted within said shell.

UNITED STATES PATENTS McLeod Nov. 6,

Abel Feb. 20,

Peay et a1. June 19,

FOREIGN PATENTS Germany Oct. 12,

1. IN AN ELECTRICAL SWITCH OPERABLE BY A MAGNETIC ACTUATOR, THECOMBINATION COMPRISING: A SHELL; A COVER PLATE INTEGRAL WITH SAID SHELL,SAID COVER PLATE OF NON-MAGNETIC MATERIAL AND HAVING THREE APERTURESTHEREIN, ONE OF SAID THREE APERTURES BEING SUBSTANTIALLY LARGER THEN THEOTHER TWO OF SAID THREE APERTURES, SAID APERTURES BEING ARRANGED TO FORMA GENERALLY QUADRANGULAR CONFIGURATION, AND AN INSERT OF MAGNETICMATERIAL SEALED WITHIN EACH OF SAID THREE APERTURES; AN ARMATUREROTATABLY MOUNTED WITHIN AND SUPPORTED BY SAID SHELL, SAID ARMATURECOMPRISING A BODY ELEMENT OF NON-MAGNETIC MATERIAL, AN ELONGATEDPERMANENT MAGNET, A BLOCK OF UNMAGNETIZED MAGNETIC MATERIAL, AND ASWITCH ARM CARRYING A PAIR OF ELECTRICAL CONTACTS MOUNTED ON SAID BODYELEMENT; TWO ELECTRICAL CONTACTS MOUNTED WITHIN AND SUPPORTED BY SAIDSHELL; AND SAID ARMATURE SO CORRELATED TO SAID COVER PLATE THAT THELARGER ONE OF SAID THREE INSERTS IS POSITIONED OVER SAID PERMANENTMAGNET AND SAID OTHER TWO OF SAID INSERTS ARE EACH POSITIONED OVER SAIDBLOCK OF MAGNETIC MATERIAL, WHEREBY THE APPLICATION OF AN ORIENTEDMAGNETIC FIELD OF A PREDETERMINED STRENGTH ACROSS SAID COVER PLATE WILLACTUATE SAID SWITCH AND CAUSE ONE OF SAID PAIR OF ELECTRICAL CONTACTS ONSAID SWTICH ARM TO ENGAGE ONE OF SAID TWO ELECTRICAL CONTACTS SUPPORTEDBY SAID SHELL.